Samara

Samara is an Asari Justicar, and a squadmate of Commander Shepard in Mass Effect 2. She is kind and calm, but an extremely powerful Biotic. Being a justicar, Samara has to abide by a strict set of rules and principles known as The Code. The player had to choose to kill either her or her daughter, Morinth, in Mass Effect 2, however, if the player did not have a high enough Paragon or Renegade score, Samara automatically kills Morinth. If Samara was killed, Morinth would take her place on your squad with nobody but Shepard really noticing because they look exactly like each other. Samara/Morinth is confirmed to appear in Mass Effect 3 as evident in the Female Shepard trailer. However it is currently unknown how much role she has at this time.